Manifold with multiple passages and cross-counterflow heat exchanger incorporating the same

ABSTRACT

A manifold having multiple chambers for use in a cross-counterflow heat exchanger assembly includes a first member having arms extending from a base to arm ends. A second member is secured to the first member to define the manifold. The second member includes an inner plate edge that defines a first mating surface that extends inwardly along the inner plate edge from each of the plate ends to mate with arm ends. A wall extends transversely to the inner plate edge to a wall end. The wall end mates with an inner base surface to divide the interior of the manifold into a plurality of chambers. At least one lip extends transversely to the inner plate edge to define a second mating surface that extends perpendicularly from the first mating surface and mates with an inner arm surface of the arms.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to manifolds having multiple chambers. Morespecifically, the invention relates to extruded manifolds with multiplechambers and cross-counterflow heat exchangers incorporating suchmanifolds.

2. Description of the Prior Art

Air-cooling (or heating) cross-counterflow heat exchangers are oftenused in applications where space limitations restrict the surface areaof the heat exchanger. Cross-counterflow heat exchangers typicallyinclude a plurality of stacked, assembled modules, with each moduleincluding a pair of spaced manifolds interconnected by a plurality ofspaced and parallel tubes. The modules are stacked such that air flowsin a direction perpendicular to the face of the heat exchanger, and airfins are disposed between adjacent pairs of tubes for transferring heatfrom the tubes to the passing air.

Another type of cross-counterflow heat exchanger assembly is shown inU.S. Pat. No. 5,941,303, issued to James D. Gowan on Aug. 24, 1999 andhereinafter referred to as Gowan '303. Gowan '303 discloses across-counterflow heat exchanger comprising a pair of spaced andcontinually extruded manifolds. Each of the manifolds includes aninterior, and each of the manifolds includes at least one dividing wallto divide the interior into a plurality of flow paths. A plurality oftubes extends and establishes fluid communication between the pair ofmanifolds. Each of the tubes includes at least one tube divider toseparate it into a plurality of passages.

SUMMARY OF THE INVENTION

In summary, the invention provides a manifold having multiple chambersfor use in a cross-counterflow heat exchanger assembly. The manifoldincludes a first member having arms extending from a base to arm ends. Asecond member is secured to the first member to define the manifold. Thesecond member includes an inner plate edge that defines a first matingsurface that extends inwardly along the inner plate edge from each ofthe plate ends to mate with arm ends. A wall extends transversely to theinner plate edge to a wall end. The wall end mates with an inner basesurface to divide the interior of the manifold into a plurality ofchambers. At least one lip extends transversely to the inner plate edgeto define a second mating surface that extends perpendicularly from thefirst mating surface and mates with an inner arm surface of the arms.

BRIEF DESCRIPTION OF THE DRAWINGS

Advantages of the present invention will be readily appreciated, as thesame becomes better understood by reference to the following detaileddescription when considered in connection with the accompanying drawingswherein:

FIG. 1 is a perspective and partial view of the exemplary embodiment ofthe invention;

FIG. 2 is a cross-sectional view of the manifold, return manifold andthe tubes taken along line 2-2 of FIG. 1;

FIG. 3 is a plan view of the first member of the exemplary embodiment ofthe invention;

FIG. 4 is a plan view of the second member of the exemplary embodimentof the invention;

FIG. 5 is a cross-sectional view of one of the tubes taken along line5-5 of FIG. 2;

FIG. 6 is an enlarged view of the lip taken from section 6 of FIG. 2;and

FIG. 7 is a perspective view of the manifold of the exemplary embodimentof the invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the Figures, wherein like numerals indicate correspondingparts throughout the several views, an exemplary heat exchanger assembly20 is generally shown.

The exemplary heat exchanger assembly 20 includes a manifold 22generally indicated having a first member 24 at least partially definingan interior. Referring to FIG. 3, in an exemplary embodiment, the firstmember 24 is a longitudinally extending channel having a cross-sectiondefining a U-shape and presenting arms 26 integrally connected to a base28 and extending forwardly to arm ends 30. Each of the arms 26 includean inner arm surface 32 and an outer arm surface. Each of the arms 26include a stress therein to cant the arm ends 30 toward one another.

Referring to FIGS. 1 and 3, the base 28 of the first member 24 includesan inner base surface 34 and the base 28 presents a plurality of firsttube slots 36 longitudinally spaced from one another. The base 28further defines at least one opening 38 that is disposed betweenadjacent first tube slots 36. The opening 38 is generally circular incross section but may be any shape known in art. Additionally, while theexemplary embodiment shows the opening 38 being disposed betweenadjacent first tubes 40 slot, the opening 38 may be disposed in the areabetween the first tube slot 36 and the end of the first member 24. Thefirst tube slots 36 and at least one opening 38 may be formed byconventional machining methods including stamping, grinding, or milling.

Referring to FIG. 2, the assembly includes a second member 42 having aplate 44 and a wall 46 extending transversely to the plate 44. Thesecond member 42 has a cross section that defines a T-shape. The plate44 extends between plate ends 48, and transversely between an innerplate edge 50 and an outer plate edge 52. The inner plate edge 50defines a first mating surface 54 that extends inwardly along the innerplate edge 50 from each of the plate ends 48 to mate with arm ends 30.The wall 46 extends transversely to the inner plate edge 50 of the plate44 to a wall end 56. The wall end 56 is contoured to conform with theinner base surface 34 for positioning the wall end 56 against the innerbase surface 34 and the first tube slots 36 to divide the interior ofthe manifold 22 into a plurality of chambers 58, 60. The wall end 56 ofthe second member 42 defines a plurality of notches 62 being spaced tocorrespond with the first tube slots 36 of the first member 24.

The wall 46 includes at least one locking arm 96 that extends outwardlyfrom the wall end 56 to mate with at least one opening 38. The lockingarm 96 secures the second member 42 to the first member 24. The lockingarm 96 is generally circular in cross section, but may be any shapeknown in the art.

The subject invention is distinguished by at least one lip 64 thatextends transversely to the inner plate edge 50 to define a secondmating surface 66, and thus creating a boot shape as seen in FIG. 4. Thesecond mating surface 66 extends perpendicularly from the first matingsurface 54 and mates with the inner arm surface 32 of the arms 26. Thecanted arms 26 of the first member 24 create a clamping force F on thesecond mating surface 66 of the lip 64 to temporally securing the secondmember 42 to the first member 24 before brazing the first and secondmembers 24, 42 together. The second member 42 is then permanently fixedto the first member 24 to form the manifold 22. In the exemplaryembodiment, the second member 42 is brazed to the first member 24, butany other method of permanently fixing the first and second members 24,42 may also be used. The manifold 22 extends longitudinally betweenfirst and second manifold ends 68, 70. The second member 42 defines alongitudinally extending groove 72 that extends between the first andsecond mating surfaces 54, 66 for accommodating a burr between the firstand second members 24, 42.

Prior to brazing the first member 24 to the second member 42 to a cap 98is disposed on each of the first and second manifold ends 68, 70 of themanifold 22. In addition to the clamping force F of the first member 24on the second member 42, the cap 98 temporally secures the manifold 22prior to being permanently secured.

The heat exchanger assembly 20 further includes a plurality of tubes 40extending between first and second tube ends 74, 76. The first tube end74 of each tube 40 is disposed in one of the first tube slots 36 of themanifold 22. Referring to FIG. 5, each tube 40 defines at least one tubedivider 78 disposed in the tube 40 and extending between the first andsecond tube ends 74, 76 to define a first passage 80 in fluidcommunication with one of the chambers 58, 60 of the manifold 22 and asecond passage 82 in fluid communication with the other of the chambers58, 60 of the manifold 22. The tube divider 78 at the first tube end 74abuts and is permanently fixed to the notches 62 in the wall end 56 ofthe second member 42.

The assembly further includes a return manifold 84 extending in spacedand parallel relationship with the manifold 22. The return manifold 84presents a plurality of second tube slots 86 longitudinally spaced fromeach other to correspond with the spacing of the first tube slots 36 ofthe manifold 22. The second tube end 76 of each tube 40 extends into andengages the corresponding second tube slot 86 to establish fluidcommunication between the tubes 40 and the return manifold 84. Thereturn manifold 84 directs the flow of coolant from one of the passagesof the tubes 40 to the other of the passages to define a two-passcross-counterflow heat exchanger assembly 20. In an exemplaryembodiment, the return manifold 84 is D-shaped to direct the flow ofcoolant from the one passages of the tubes 40 to the other passage ofthe passages, but the return manifold 84 may be any shape known in theart.

In the exemplary embodiment, the tubes 40 and the first and second tubeslots 36, 86 each have a cross-section presenting parallel flat sides 88that extend between round ends. However, the tubes 40 may be have anyshape capable of transmitting a fluid between the first and secondmanifold 22. The flat sides 88 of adjacent tubes 40 are spaced from oneanother to define a plurality of air passages for the flow of airtherebetween. A corrugated air fin 90 is disposed between and brazed tothe parallel flat sides 88 of adjacent tubes 40 and extends between thefirst and return manifolds 22, 84 for dissipating heat from the tubes40.

One of the chambers 58, 60 of the manifold 22 includes an input 92 incommunication with an input chamber 58 for receiving a fluid, and anoutput 94 in communication with an output chamber 60 for dispensing thecoolant after it has passed through the heat exchanger assembly 20. Inan exemplary embodiment, the input 92 is disposed on the input chamber58 that is downstream of the direction of the flow of air and the output94 is disposed on the output chamber 60 upstream of the input chamber58. The input 92 and output 94 may have any shape capable of deliveringa fluid to the input chamber 58 and output chamber 60 of the manifold22.

The embodiment shown in the drawings is for a two-pass countercross-flow heat exchanger assembly. However, the manifolds and tubes maybe designed to allow for more than two passes by inserting walls ineither or both of the first and return manifolds and including aplurality of tube dividers in each tube. For example, in a three-passheat exchanger assembly, the second member has one wall to divide themanifold into two chambers, the return manifold has one wall, and eachtube has two tube dividers.

The invention also includes a method of forming a manifold 22 for use ina heat exchanger assembly 20. The method starts with the step ofseparately forming a first member 24 at least partially defining aninterior and a second member 42. The first member 24 has a spaced set offirst tube slots 36 and the second member 42 has a wall 46 that ispositioned against the first tube slots 36 to divide the interior into aplurality of chambers 58, 60.

Next, the first member 24 is temporally secured to the second member 42.The arm ends 30 of the first member 24 are rolled to be canted towardone another. This creates a stress in the arms 26 of the first member 24so that when the inner arm surface 32 of the first member 24 is broughtinto contact with the second mating surface 66 of the lip 64 of thesecond member 42, the first member 24 will be secured to the secondmember 42.

The method may further include the step of placing a cap 98 on each ofthe first and second manifold ends 68, 70. The shape of the cap 98 iscontoured to mate with the outer periphery of the first and secondmanifold ends 68, 70. The cap 98 temporally secures the first member 24to the second member 42 by the clamping force F.

The method continues with the step of permanently fixing the firstmember 24 to the second member 42 to define a manifold 22 after thetemporally securing step. The second member 42 is preferably extrudedand then cut to size, but may also be formed by other methods includingcasting and machining. In one embodiment, the forming the first member24 is further defined as rolling a flat sheet of material into a channelhaving a cross-section presenting a U-shape and having a base 28 andarms 26 extending forwardly to arm ends 30. Rolling the first member 24from a flat sheet provides advantages because the flat sheet can be astock sheet of metal with a brazing material pre-disposed on either sideof it. The brazing material then may be used for the step of permanentlyfixing the first member 24 to the second member 42.

The method proceeds with the step of forming a plurality of tubes 40extending between first and second tube ends 74, 76. The method thencontinues with the step of forming a tube divider 78 extending betweenthe first and second tube ends 74, 76 in each of the tubes 40 toseparate each tube 40 into a first passage 80 and a second passage 82.Referring to FIG. 5, in one embodiment, the forming each tube 40 isfurther defined by rolling a flat sheet of material into a tube 40defining a tube divider 78. Rolling each tube 40 from a flat sheetprovides advantages because the flat sheet can be a stock sheet of metalhaving a pre-disposed brazing material on either side of it. The brazingmaterial may then later be used for the step of fixing and sealing thetube ends 74, 76 to the first and second tube slots 36, 86 of themanifolds 22, 84. However, any other method of forming the tube divider78 may also be used.

The method continues with the step of inserting the first tube end 74 ofeach tube 40 into one of the first tube slots 36 of the manifold 22 andabutting the divider of each tube 40 against the wall 46 of the secondmember 42 to establish fluid communication between the first passage 80of the tubes 40 and one of the chambers 58, 60 of the manifold 22 and toestablish fluid communication between the second passage 82 of the tubes40 and the other of the chambers 58, 60 of the manifold 22. The firsttube end 74 of each tube 40 is then permanently fixed to the associatedfirst tube slot 36 manifold 22.

The method further continues with the step of forming a return manifold84 having a set of second tube slots 86 being spaced from each other tocorrespond with the set of first tube slots 36 of the manifold 22. Themethod proceeds with the step of inserting the second tube end 76 ofeach of the tubes 40 into the corresponding second tube slot 86 of thereturn manifold 84 to establish fluid communication between the firstand second passages 80, 82 of each tube 40 and the return manifold 84.

The method is finished with the steps of forming a plurality of air fins90 and inserting one of the air fins 90 between adjacent tubes 40 todissipate heat from the tubes 40. In the exemplary embodiment, the tubes40, manifold 22, and air fins 90 are all brazed together to define aunified heat exchanger assembly 20.

The subject invention provides for a manifold and a cross-counterflowheat exchanger assembly 20 that is both cheaper and quicker tomanufacture than those of the prior art. Additionally, the exemplaryembodiment provides a more sturdy structure prior to and followingbrazing. Many of the traditional methods for forming the tube slots inthe manifold of the Gowan '303 patent must be abandoned in order toavoid interfering with the dividing wall of the manifold. The first tubeslots of the Gowan '303 patent must be milled or grinded, either ofwhich is a very time consuming and costly process. The first tube slots36 of the present invention may be formed in the first member 24 using avariety of manufacturing methods including stamping before the step ofpermanently fixing the first and second members 24, 42 together. Thisleads to significantly greater manufacturing efficiency, therebyreducing the cost and time to assemble the manifold 22 and of the heatexchanger assembly 20.

While the invention has been described with reference to an exemplaryembodiment, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiment disclosed as the best modecontemplated for carrying out this invention, but that the inventionwill include all embodiments falling within the scope of the appendedclaims.

1. A manifold for use in a heat exchanger assembly comprising: a firstmember presenting arms integrally connected to a base having an innerbase surface, each of said arms having an inner arm surface andextending from said base to an arm end; a second member secured to saidfirst member to define said manifold, said second member having a plateextending between plate ends and between an inner plate edge and anouter plate edge, and said inner plate edge defining a first matingsurface extending inwardly along said inner plate edge from each of saidplate ends to mate with arm ends; a wall extending transversely to saidinner plate edge of said plate to a wall end, said wall end mating withsaid inner base surface to divide the interior of said manifold into aplurality of chambers; and at least one lip extending transversely tosaid inner plate edge of said second member to define a second matingsurface that extends perpendicularly from said first mating surface andmates with said inner arm surface of said arms.
 2. The manifold as setforth in claim 1 wherein each of said arms includes a stress therein tocant said arm ends toward one another and wherein said canted armscreate a clamping force on said second mating surface of said lip fortemporally securing said second member to said first member.
 3. Themanifold as set forth in claim 1 wherein said base defines a pluralityof longitudinally spaced first tube slots and at least one openingdisposed between adjacent ones of said first tube slots.
 4. The manifoldas set forth in claim 3 wherein said wall end is contoured to conformwith said inner base surface for positioning said wall end against saidinner base surface and said first tube slots.
 5. The manifold as setforth in claim 4 wherein said wall end of the second member defines aplurality of notches being spaced to correspond with said first tubeslots of said first member.
 6. The manifold as set forth in claim 3wherein said wall includes at least one locking arm extending from saidwall end to mate with said at least one opening to secure said secondmember to said first member.
 7. The manifold as set forth in claim 1wherein said manifold extends longitudinally between first and secondmanifold ends.
 8. The manifold as set forth in claim 7 including a capdisposed at each of said first and second manifold ends.
 9. The manifoldas set forth in claim 1 further including an input in communication withan input chamber for receiving a fluid and an output in communicationwith an output chamber for dispensing the fluid.
 10. The manifold as setforth in claim 1 wherein said second member defines a longitudinallyextending groove between said first and second mating surfaces foraccommodating a burr between said first and second members.
 11. Across-counterflow heat exchanger assembly comprising: a first memberpresenting arms integrally connected to a base having an inner basesurface, each of said arms having an inner arm surface and extendingfrom said base to an arm end, said base defining a plurality oflongitudinally spaced first tube slots; a second member secured to saidfirst member to define a manifold, said second member having a plateextending between plate ends and between an inner plate edge and anouter plate edge, and said inner plate edge defining a first matingsurface extending inwardly along said inner plate edge from each of saidplate ends to mate with arm ends; a wall extending transversely to saidinner plate edge of said plate to a wall end, said wall end mating withsaid inner base surface to divide the interior of said manifold into aplurality of chambers; at least one lip extending transversely to saidinner plate edge of said second member to define a second mating surfacethat extends perpendicularly from said first mating surface and mateswith said inner arm surface of said arms; a return manifold extending inspaced and parallel relationship with said manifold and defining aplurality of longitudinally spaced second tube slots to correspond withsaid first tube slots of said manifold; a plurality of tubes extendingbetween first and second tube ends, each of said first tube endsengaging each of said first tube slots and each of said second tube endsengaging each of said second tube slots to establish fluid communicationbetween said manifold and said return manifold, and wherein adjacenttubes are spaced from one another to define a plurality of air passagesfor the flow of air between said adjacent tubes; and an air fin disposedbetween and brazed to said tubes and extending between said manifold andsaid return manifold for dissipating heat from said tubes.
 12. Theassembly as set forth in claim 11 wherein each of said tubes define atube divider extending between said first and second tube ends to definea first passage in fluid communication with one of said chambers of saidmanifold and a second passage in fluid communication with the other ofsaid chambers of said manifold.
 13. The assembly as set forth in claim11 wherein said wall end of the second member defines a plurality ofnotches being spaced to correspond with said first tube slots of saidfirst member and wherein said tube divider at said first tube end abutssaid notches of said wall end of said second member.
 14. The assembly asset forth in claim 11 wherein each of said tubes has a cross-sectiondefining parallel flat sides extending between round ends.
 15. A methodof forming a manifold for use in a heat exchanger assembly including thesteps of: separately forming a first member at least partially definingan interior and having a spaced set of first tube slots and a secondmember having a wall positioned against the first tube slots anddividing the interior into a plurality of chambers; temporarily fixingthe first member to the second member to define a manifold extendingbetween first and second manifold ends after the separately formingstep; and permanently fixing the first member to the second member. 16.The method as set forth in claim 15 wherein the temporarily fixing stepis further defined as canting arms of the first member inwardly tocreate a stress therein and on a second mating surface defined by a lipon said second member.
 17. The method as set forth in claim 15 furtherincluding the step of: placing a cap on the first and second manifoldends prior to the permanently fixing step.
 18. The method as set forthin claim 15 wherein the forming the first member is further defined asrolling a flat sheet of material into a channel having a cross-sectionpresenting a U-shape presenting a base and arms extending forwardly toarm ends.